Cells or batteries having a lithium anode and an iodine-containing cathode are well known and have been used extensively to provide power to low-power-demand electronic circuits, including heart pacers. Ordinarily the anode and cathode are brought into direct contact and a solid LiI electrolyte forms in situ to separate the anode and cathode while keeping them in electrochemical contact to generate power. Such cells are described, for example,in U.S. Pat. Nos. 3,660,163, 3,674,562, 4,148,975, 4,276,372, and 4,952,469. It is conventional in such cells to use a metal screen anode current collector and lead wire extending through the battery housing. To prevent short circuiting, U.S. Pat. No. 3,874,929 encloses the lead wire in a metal ferrule and insulating sleeve to seal it from migrating plastic or fluid cathode material. We have discovered another failure mechanism caused by iodine vapor in the cell even when the cathodes are in the solid state and do not migrate. If the iodine vapor reaches the interface of the current collector and anode, a lithium iodide film is formed at the interface that can separate the current collector from the anode. This results in a loss of electrical output from the battery.